US3689802A - Apparatus for supervising the functioning of an analog plural-channel regulating system - Google Patents

Apparatus for supervising the functioning of an analog plural-channel regulating system Download PDF

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Publication number
US3689802A
US3689802A US135933A US3689802DA US3689802A US 3689802 A US3689802 A US 3689802A US 135933 A US135933 A US 135933A US 3689802D A US3689802D A US 3689802DA US 3689802 A US3689802 A US 3689802A
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paths
mean
output
set forth
control
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Hermann Waldmann
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B9/00—Safety arrangements
    • G05B9/02—Safety arrangements electric
    • G05B9/03—Safety arrangements electric with multiple-channel loop, i.e. redundant control systems

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  • ABSTRACT The mean value of the amplitude of analog signals appearing on individual control paths is continuously formed.
  • Three-level switch means are provided which are addressed by groups of two control path voltages of the individual control paths, and a disturbed control path is disconnected by the switch means, and either the output signal of the mean-value forming unit or one of the remaining connected input signals is weighted, so that failure of one control path does not significantly afiect the output signal of the mean-value forming unit which is supplied to following apparatus.
  • the failure of a control path can occur without interruption or significantly changing the operation of this supervisory apparatus. This failure can sound an alarm which pinpoints the specific location of the fault.
  • An object of my invention is to provide a more accurate supervisory apparatus inserted directly in the paths of the signals supervised.
  • Another object of my invention is to provide a supervisory apparatus which, when a fault is sensed in one of the paths, produces an output signal for all the paths which is approximately the actual values thereof.
  • Still another object of my invention is to provide a supervisory apparatus in which a fault in one of the control paths being supervised does not substantially affect the operation of the supervised paths.
  • Another object of my invention is to provide a supervisory apparatus which pinpoints the location of the fault.
  • Still another object of my invention is to provide a supervisory apparatus which is less sensitive to harmonic and and other noise carried on the control paths and which may cancel such noise when a fault is detected.
  • Yet another object of my invention is to provide a supervisory apparatus which may be used to supervise any n number of control paths in a great variety of environments.
  • the above objects are accomplished by providing a supervisory apparatus having two-out-of-three selection, with continuous mutual comparison of the individual control paths and undisturbed transmission of the analog signal in the event of failure of one control path.
  • all control paths are fed disconnectibly to the inputs of a mean-value forming unit.
  • Three-level switches are always connected with two control paths and actuate switching means for disconnecting one control path from the input of the mean-value forming unit and for simultaneously changing the weighting of either its output signal or of one of its input signals supplied by the remaining control paths.
  • FIG. 1 is a schematic diagram of an embodiment of the two-out-of-three selection process of the supervisory apparatus of my invention
  • FIG. 2 is another embodiment of the supervisory apparatus of my invention
  • FIG. 3 is a block diagram in which the supervisory apparatus of my invention is utilized
  • FIG. 4 is a schematic diagram of another embodiment in which the supervisory apparatus of my invention may be utilized.
  • FIG. 5 is a schematic diagram of a threshold level director used with the supervisory apparatus of my invention.
  • the input terminals 11, 12 and 13 of a supervisory apparatus, in accordance with my invention, designated KK( control and correction unit) and to practical advantage combined in one module, are connected with three paths S1, S2 and S3 of a three-channel control system.
  • the paths can originate in preceding elements of the control system, not shown in detail, such as actual and preset-value transmitters, control amplifiers or other signal transmission devices.
  • Terminals 11 and 12 are connected with the inputs of a three-level switch 14, at the output of which there appears an output signal actuating a relay A, if the difference of the voltages appearing at the terminals 11 and 12 exceeds a small, presettable threshold value.
  • Terminals 12, 13 and 11, 13, respectively, are connected with the additional three-level switches 15 and 16 to energize the coils of the relays B and C, respectively, in a similar manner.
  • the amplifier 17 in an unloaded condition has a very large gain and has a negative feedback via a resistor R, the resistance value of which is one-third of that of each of the input resistors 3R of the operational amplifier.
  • the operational amplifier 17, thus, functions as a meanvalue forming unit inasmuch as the arithmetic mean of the voltages applied to its input resistors 3R appears at its input terminal 18. If all the control paths are undisturbed, the voltage appearing at the output terminal 18 practically corresponds to each of the individual control path voltages.
  • the threshold alarms 14 and 16 respond and actuate the relays A and C.
  • the voltages at the terminals 12 and 13 would now be connected via the double-throw contacts a and b with the input resistors 3R of the operational amplifier 17, while the input previously connected with the terminal 11 of the operational amplifier I7 is disconnectd therefrom and is now connected to the terminal 12.
  • the voltage which exists at the terminal 12 thus also feeds the operational amplifier 17. Therefore, in forming the mean value in the operational amplifier 17, the input signal of terminal 12 carries twice the weight as that of terminal 13. The output signal at the terminal 18 therefore remains unaffected by the disengagement or fault on the disturbed path S1.
  • a signal lamp Ll may be connected to an external voltage U supplied from a terminal 19, via two make contacts of the relays A and C which are actuated in case of a disturbance in the path S1.
  • the control and correction units KK shown in FIG. 1 are used within one control system, it is desirable to provide one signal lamp L at a central point which is assigned to all such supervisory arrangements and would be connected with the terminal designated 20 of such an apparatus.
  • the make contacts of all existing alarm relays would therefore be connected in parallel between this terminal 20 and the respective reference potential terminals 21, so that voltage is applied to the central signal lamp L even if only one of the relays A, B or C in the individual supervisory units KK pulls up.
  • the central signal lamp L, as well as two of the lamps assigned to the respective supervisory unit KK will light.
  • the central lamp L may consist of an alarm relay which is actuated, in order to enhance the operating reliability, not by the parallelconnected make contacts of the relays A to C but serially connected break contacts of these relays (holding current principle). The operational reliability of the installation can thereby be increased further.
  • FIG. 2 another embodiment of the supervisory apparatus according to my invention is shown, which realizes the principle of mean-value formation with uniform participation of all control path voltages acting on the mean-value forming unit also for the disturbed case.
  • the corresponding reference symbols of FIG. 1 are retained.
  • the threshold indicators 14 to 16, as well as the relays A to C, are energized in exactly the same manner as in the arrangement shown in FIG. 1.
  • the circuit part related to the fault indication has been substantially retained and a horn designated H may also be used as the central warning device.
  • the sum of the input voltages originating in the two undisturbed control paths is multiplied by the operational amplifier by a factor of /2 through the opening of the break contact a, c, a, b or b, c and is passed on to the output terminal 18.
  • a different weighting of the output signal of the mean-value forming unit therefore, is accomplished relative to the sum of its input signals.
  • FIG. 2 The essential difference of FIG. 2 re the arrangement of FIG. 1 consists in that the path voltages to be connected to the input terminals 11, 12 and 13 are fed, via the parallel circuit of break contacts, to the input resistors of those two relays, which respond in case of a disturbance in the path in question, and that by a seriesparallel circuit of further break contacts of these relays, the negative feedback resistance of the operational amplifier 17 is, in part, varied in such a manner, that upon disconnecting one control path from the input of the amplifier, the gain of the latter increases by a factor of 3/2 relative to the undisturbed condition.
  • the two-out-of-three selection monitoring circuit could readily be expanded to a three-out-of-four selection monitoring circuit or, generally, to an N-l )-0utof-nselection monitoring circuit.
  • a total of six or in general, n( n- 1) k) three-level switches would be required for any possible combination of two path voltages, and break contacts of the respective three or in general, nl) relays that can be influenced by a path voltage would have to be connected in parallel in the input and negative feedback circuit of the operational amplifier 17 in a manner analogous to FIG. 2.
  • the input resistor and the parts of the negative feedback resistance that can and cannot be bridged would have the ratio 4 l ,4; or in general n l l/n -l
  • a three-out-of-four system offers a higher degree of reliability than the twoout-of-three system, it is substantially more expensive, so that it appears that its use would be limited, for example, to the field of reactor technology.
  • the function-supervising apparatus could be used in a control system with three paths in such a manner that three output signals of the mutually corresponding control circuit elements in the three control paths are controlled or corrected by only one monitoring arrangement, and the output signal of the latter is fed in parallel to the inputs of three following, signal-processing control circuit elements.
  • the supervisory function according to the two-out-of-three selection process would not include the control and correction members themselves because with such an arrangement, the separation of the three-channels of the control system would be violated. It is therefore practically advantageous to provide a control and correction circuit for each signal-processing control circuit element, so that three correction circuits are always addressed in parallel by the output of a control circuit element.
  • FIG. 3 shows the schematic diagram of such an arrangement.
  • the output quantities 1.1, 1.2, and 1.3 of three similarly constructed reference value transmitters are processed by a remote-transmission arrangement 2 into the output signals 2.1, 2.2 and 2.3 which address three control and correction members KK according to FIG. 1 or FIG. 2.
  • the outputs 3.1, 3.2 and 3.3 act as reference values for three mixers designated 6, to which are fed output quantities 5.1, 5.2 and 5.3 of further function supervising units KK which are fed in an analogous manner by three actual-value transmitters designated 4.
  • three further supervisory units KK are respectively provided which at their inputs are connected in a corresponding manner with the outputs of the control system elements preceding them.
  • the system shown in FIG. 3 permits continuous supervision and simple and unambiguous fault location, as the occurrence of trouble is reported by the central warning device and the trouble location can be determined by the signal lamps L1 to L3 assigned to the individual sections of the control circuit.
  • each of the integrating controls 22, 23 and 24 arranged in the three controlled systems provide, by means of a negative feedback resistor R, connected with the input of the correction and supervisory circuit KK a static condition, which is normally fully compensated by positive feedback from the output 18 of the mean-value forming unit via a resistor R,,, of the same magnitude as R,
  • the mentioned tolerances in the signal deviation then take effect only to the extent that the output voltages of the three integrating controls 22 to 24 showing slight differences, which can be taken into account by suitable adjustment of the response limits of the three-level switches in the control and correction circuits KK.
  • FIG. 5 An example of an embodiment of the three-level switch designated 14 to 16 in FIGS. 1 and 2 is shown in FIG. 5.
  • the switch consists of an operational amplifier 25, the input terminals 26 and 26 of which are fed the voltages to be compared with each other.
  • the output of the amplifier is connected via a low-resistance potentiometer 28 to a reference potential with the tap of the potentiometer connected to a negative feedback resistor 29.
  • the negative feedback resistor 29 as well as the other resistors connected with the amplifier inputs designated with +and are of the same magnitude.
  • the amplifier output is connected via two series-connected diodes 30, for example, Zener diodes, with the input of an amplifier 31 of such high gain that its output voltage practically assumes its maximum, either positive or negative, if the input voltage is different from zero.
  • diodes 30, for example, Zener diodes the input of an amplifier 31 of such high gain that its output voltage practically assumes its maximum, either positive or negative, if the input voltage is different from zero.
  • the potentiometer 28 adjustably by the potentiometer 28, of the voltages applied to the input terminals 26 and 27, the breakdown voltage of one of the diodes 30 is exceeded, so that the output signal of the amplifier 31 suddenly jumps to its output limit.
  • the functions indicated in the block diagram for the elements 14 and 16 in FIGS. 1 and 2 can thus be achieved in this manner.
  • Apparatus for supervising the operation of a plurality of control paths of an analog plural-channel regulation system and sensing a failure in one of said paths comprising comparison means for continuously comparing the signal amplitudes on pairs of said plurality of control paths, mean-value forming means for receiving said signal amplitudes as inputs and forming an output which is the mean of the inputs applied thereto, said output being at an output level without a failure on any of said paths, and switch means responsive to a predetermined difference between said compared pairs for disconnecting one of said control paths from said mean-value forming means and maintaining the output of said mean-value forming means at approximately the output level when a failure occurs in one of said paths.
  • said mean-value forming means comprises an operational amplifier and a feedback resistor, said switching means changing the resistance of said feedback resistor responsive to the occurrence of a fault in one of said paths.
  • Apparatus as set forth in claim 1, comprising a plurality of warning means with respective ones of said warning means associated with respective ones of said plurality of paths, said one of said warning means being energized when a failure occurs in an associated control path.
  • Apparatus as set forth in claim 1, comprising integrating members within said control paths, the inputs of said mean-value forming means being coupled through a negative feedback coupling to the input of an integrating member, the output of said mean-value forming unit being coupled through a positive feedback coupling to the input of said integrating member.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Safety Devices In Control Systems (AREA)
  • Monitoring And Testing Of Nuclear Reactors (AREA)
  • Measurement Of Current Or Voltage (AREA)
  • Feedback Control In General (AREA)
  • Selective Calling Equipment (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
US135933A 1970-04-29 1971-04-21 Apparatus for supervising the functioning of an analog plural-channel regulating system Expired - Lifetime US3689802A (en)

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Application Number Priority Date Filing Date Title
DE19702020940 DE2020940B2 (de) 1970-04-29 1970-04-29 Einrichtung zur funktionsueberwachung der einzelnen regelstraenge eines analogen mehrkanaligen regelsystems

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JP (1) JPS5123287B1 (enrdf_load_html_response)
AT (1) AT315309B (enrdf_load_html_response)
BE (1) BE766420A (enrdf_load_html_response)
CA (1) CA934667A (enrdf_load_html_response)
CH (1) CH558564A (enrdf_load_html_response)
DE (1) DE2020940B2 (enrdf_load_html_response)
FR (1) FR2086455B1 (enrdf_load_html_response)
GB (1) GB1358592A (enrdf_load_html_response)
NL (1) NL7105134A (enrdf_load_html_response)
NO (1) NO128928B (enrdf_load_html_response)
RO (1) RO63746A (enrdf_load_html_response)
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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3895223A (en) * 1973-01-03 1975-07-15 Westinghouse Electric Corp Circuit arrangement for enhancing the reliability of common bus outputs of plural redundant systems
US3979720A (en) * 1974-05-22 1976-09-07 Siemens Aktiengesellschaft Apparatus for monitoring a redundant multi-channel analog system
US3979256A (en) * 1975-03-04 1976-09-07 The United States Of America As Represented By The United States Energy Research And Development Administration Monitoring circuit for reactor safety systems
US4143353A (en) * 1976-07-07 1979-03-06 Bbc Brown, Boveri & Company Limited Apparatus for the supervision or correction of electrical signals
US4186048A (en) * 1976-09-07 1980-01-29 General Atomic Company Neutron flux monitoring system
US4199799A (en) * 1978-03-24 1980-04-22 General Electric Company Supervisory circuit for redundant channel control systems
US4264955A (en) * 1978-11-03 1981-04-28 The United States Of America As Represented By The United States Department Of Energy Signal voter
US4302288A (en) * 1978-10-23 1981-11-24 General Electric Company Fluid level control system
US4427620A (en) 1981-02-04 1984-01-24 Westinghouse Electric Corp. Nuclear reactor power supply
US4562035A (en) * 1980-11-26 1985-12-31 Commissariat A L'energie Atomique Logic safety system
US4577332A (en) * 1983-03-14 1986-03-18 General Electric Company Digital decoding arrangement
US20070109012A1 (en) * 2005-10-27 2007-05-17 Honeywell International Inc. Voting scheme for analog signals

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0033785A1 (fr) * 1980-02-08 1981-08-19 ATELIERS DE CONSTRUCTIONS ELECTRIQUES DE CHARLEROI (ACEC) Société Anonyme Installation de commande de sécurité de processus industriel
DE3145162A1 (de) * 1981-11-13 1983-05-26 AEG-Kanis Turbinenfabrik GmbH, 8500 Nürnberg Verfahren zur messung und ueberwachung der drehzahl von schnellaufenden maschinen
JPS6455608U (enrdf_load_html_response) * 1987-09-30 1989-04-06
FR2680068A1 (fr) * 1991-08-02 1993-02-05 Aerospatiale Selecteur de signaux a trois entrees, application a un selecteur a n entrees ainsi qu'a un voteur a n entrees.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1280431B (de) * 1966-10-20 1968-10-17 Siemens Ag Regeleinrichtung in Kernreaktoranlagen
US3544778A (en) * 1967-11-29 1970-12-01 Westinghouse Electric Corp Decision network

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH384098A (de) * 1960-09-12 1964-11-15 Landis & Gyr Ag Einrichtung zur Überwachung des Neutronenflusses in einem Atomreaktor
FR1437417A (fr) * 1964-12-23 1966-05-06 Thomson Houston Comp Francaise Perfectionnements aux appareils de mesures du type à comparaison

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1280431B (de) * 1966-10-20 1968-10-17 Siemens Ag Regeleinrichtung in Kernreaktoranlagen
US3544778A (en) * 1967-11-29 1970-12-01 Westinghouse Electric Corp Decision network

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3895223A (en) * 1973-01-03 1975-07-15 Westinghouse Electric Corp Circuit arrangement for enhancing the reliability of common bus outputs of plural redundant systems
US3979720A (en) * 1974-05-22 1976-09-07 Siemens Aktiengesellschaft Apparatus for monitoring a redundant multi-channel analog system
US3979256A (en) * 1975-03-04 1976-09-07 The United States Of America As Represented By The United States Energy Research And Development Administration Monitoring circuit for reactor safety systems
US4143353A (en) * 1976-07-07 1979-03-06 Bbc Brown, Boveri & Company Limited Apparatus for the supervision or correction of electrical signals
US4186048A (en) * 1976-09-07 1980-01-29 General Atomic Company Neutron flux monitoring system
US4199799A (en) * 1978-03-24 1980-04-22 General Electric Company Supervisory circuit for redundant channel control systems
US4302288A (en) * 1978-10-23 1981-11-24 General Electric Company Fluid level control system
US4264955A (en) * 1978-11-03 1981-04-28 The United States Of America As Represented By The United States Department Of Energy Signal voter
US4562035A (en) * 1980-11-26 1985-12-31 Commissariat A L'energie Atomique Logic safety system
US4427620A (en) 1981-02-04 1984-01-24 Westinghouse Electric Corp. Nuclear reactor power supply
US4577332A (en) * 1983-03-14 1986-03-18 General Electric Company Digital decoding arrangement
US20070109012A1 (en) * 2005-10-27 2007-05-17 Honeywell International Inc. Voting scheme for analog signals
US7579879B2 (en) * 2005-10-27 2009-08-25 Honeywell International Inc. Voting scheme for analog signals

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CA934667A (en) 1973-10-02
RO63746A (fr) 1979-02-15
GB1358592A (en) 1974-07-03
CH558564A (de) 1975-01-31
FR2086455B1 (enrdf_load_html_response) 1974-04-26
ZA712629B (en) 1972-01-26
AT315309B (de) 1974-05-27
NL7105134A (enrdf_load_html_response) 1971-11-02
NO128928B (enrdf_load_html_response) 1974-01-28
SE379869B (enrdf_load_html_response) 1975-10-20
DE2020940B2 (de) 1973-05-03
FR2086455A1 (enrdf_load_html_response) 1971-12-31
SU414820A3 (enrdf_load_html_response) 1974-02-05
DE2020940A1 (de) 1971-11-11
JPS5123287B1 (enrdf_load_html_response) 1976-07-15
BE766420A (fr) 1971-09-16

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